This invention relates generally to the field of reinforcing fibers and more particularly to a process and apparatus for spreading a multiple filament tow into a spread web by subjecting the multiple filament tow to a cyclical high velocity impact with the spreading rollers which result in spreading of the tow band.
In the composites industry, a tow is an untwisted bundle of continuous filaments, and it refers to man-made fibers, particularly carbon fibers. Tows are designated by the number of fibers they contain. For example, a 12K tow contains about 12,000 fibers. Multiple filament tows are often used for producing fiber reinforced plastic materials. Examples of such fibers are carbon, glass, and aramids. Such fibers have low mass and a relatively high tensile strength in their longitudinal direction. These fibers are often embedded in a plastic matrix with a matrix resin for producing such products as golf clubs, fishing rods, automotive components, and aeronautical applications.
Such fibers are generally supplied from the manufacturer in the form of multiple filament tows which are wound into a spool for handling on traditional textile equipment.
It has been found desirable to lessen the density of such tows for ease of resin impregnation, lessen expense by utilizing heavier tows and spreading to result in similar products obtained by lighter tows, and produce thinner density materials to reduce weight materials. Various prior art devices and processes have been carried out for spreading such tows to reduce the density thereof